I just took a quick look and as I'm not based where you are I can only try and replicate the results by looking for "zinc roofing essex" or "zinc roofing halstead".
For both I see your listing come up (ish) so it is recognised for zinc roofing searches.
Can I ask you to see how the results differ for you when you search on your desktop and on your phone? The location targeting on your phone is more accurate. Do you appear when searching for "zinc roofing" on your phone?
When I search with "essex" in the search phrase I see that you are quite far away from other businesses. That can also be a factor.
However, you need to tidy the GMB listing first before anything else.
The address on the listing is incomplete compared to what's on the website. You need to match the two. It's missing the street number.
You have put that you are open 24 hours which is not true and your competitors have proper times selected. Update your times to be actual business times.
Your business description in the listing looks like spam:
"'All Metal Roofing Services, free quotes, estimates and advice Zinc roofing Copper roofing Stainless Steel roofing TCS roofing Leadwork Lead Roofing Lindab PLX roofing GreenCoat PLX roofing Zinc Roof Copper Roof Stainless Steel Roof TCS Roof Lindab Roof GreenCoat Roof PLX Roof Lead Roof Cladding Essex Suffolk Hertfordshire Cambridgeshire mail:mailto:
[email protected] Tel.07427026090'
This is not a quality description of your business. Rewrite it as a helpful, friendly and useful description of your business and the services that you offer. Imagine telling your best friend what you do....write it like that.
I suspect because as the listing is incomplete, it's looks a little spammy and the opening hours are not true, that it may have lost trust and so it's not appearing perhaps as much as it should do.
I would start by improving your business listing as that may just increase the trust in your listing and get you appearing more often in searches again.